I spent so much time in reading PDF, so I need an anotation feature.
I like how Okular save the anotation in xml file, so I can easily share my clean PDF, and export anotation when I need.
now I use Evince to avoid KDE dependency, because Evince now support annotation (Highlight, Note).
But, how to remove all annotation at once, it's a pain if I have to keep 2 same PDF just to make me easy to share the clean one.
Note: Foxit support deleting all annotations at once, but I tried to use the libre application first.